Double-acting two-stroke internal-combustion engine



Feb. 22, .1927. P" KU'YKEN 1618,345

DOUBLE ACTING TWO-STROKE INTERNAL COMBUSTION ENGINE Filed Apg. 22, 1924 fwre afar;

' Z MW, v W

Patented Feb. 22, 1927.

UNITED STATES 1,618,345 PATENT orries.

rrn'rnn KUYKEN, or marinara, NETHERLANDS.

DOUBLIil-ACTING .EEWO-STROKE INTERNAL-COMBUSTION ENGINE.

Application filed August 22, 1924, Serial No. 233,624, and in the Netherlands January 31, 1924.

M two-Ztroke internal combustion engines having scavenging air ports in the middle re gion of the cylinder wall.

In order that the cylinder ofa two-stroke internal combustion engine may be efiiciently scavenged through an air port .or ports disposed opposite the outlet it is essential that the air should flow, as nearly as possible, in the direction of the axis of'the cylinder to expel the combustion gases from the combustion space.

In a double-acting engine the scavenging air should be directed alternately towards the one and the other end of the cylinder. This desideratuni may be realized with the employment of two series of ports having their axes suitably inclined towards the corresponding cylinder'ends, but this construction requires an appreciable extension of the cylinder and involves the employment 01"" acomparatively long and heavy piston. Also the arrangement of a rotary valve controlling a single series of scavenging air ports of greater axial length than the exhaust ports is open to like criticism.

My invention has for its "object to provide an improved arrangement for effective scavenging of the cylinder with only one scavenging port or series of ports. With this object in view I provide a guide member movable laterally and more or less parallel to the axis of the cylinder and cooperating with the scavenging ports, saidguide member being formed and actuated in such a manner as to direct the flow of scavenging air alternately to the one and to the other end of the cylinder. Preferably the said guide-member conforms to-the interior ofthat portion of the air inlet chamber which is adjacent to the cylinder, lining and the wallsof which are inclined to the axis of the cylinder, the length of said guide-member in the direction of the axis of the cylinder being less than that of the chamber. so that between the guide member and the inclined chamber walls inclined slots or passages are formed, through which in alternation, dependent upon the position of the guide member in the chamber, the air is caused to flow in the required direction into the cylinder assoon as the piston unmasks the scavenging port or ports. Between the guide member and the chamber walls may be inserted suitable packing, for instance partly loose leather strips, for closinvention relates to double-acting ing the narrow passage that may be left at that slde of the guide member at which the scavenging air 1s not to be discharged.

Instead of a guide member in the form of a block or displacer co-operating with the walls of the air inlet chamber to constitute nozzles for forming the air jets, a slide valve, the ports of which act as nozzles, may be used. The use of a slide valve, however, has the drawback that a slide face is difficult to be trued at this place and that it requires a compa atively spacious air chamber, whereby the water-cooled portion of the cylinder is reduced. A rotary valve cannot be used in arrangements according to the invention.

In short I prefer to employ a simple guide member to obtain the objects of my invention. Suitable actuating mechanism for such member comprises two pairs of crank arms of equal length secured to parallel shafts, one of said shafts being oscillated in timed relation with the reciprocation of the piston. The length of stroke of the guide member should be such that said member does not contact with the air chamber walls, whereby a noiseless operation is obtained and seizing is avoided.

The annexed drawing illustrates diagrammatically, and by way of example only, one embodiment of my invention.

Fig. 1 is a part elevation and part axial section of the cylinder and adjacent parts of a double-acting two-stroke internal combustion engine,

Fig. 2 is a View similar to 1, with the moving parts in difierent positions, and

Fig. 3 is a sectional view on line IIIIII of Fig. 1.

Movable in the cylinder 1 is a piston 2 shown in its lowermost position in Fig. 1, and in its uppermost position in Fig. 2.- The scavenging air is admitted into the cylinder through ports 3 and the combustion gases are expelled through ports 4. The top and bottom walls of the chamber 5 forming the end of the scavenging air conduit areconical. Said chamber accommodates an arcuate movablemember 6, that side of the member G adjacent to the eylinder presenting two correspondingly shaped conical surfaces. hen the member 6 assumes its uppermost position (Fig. 1) it leaves a conical passage 7 directing the flow of air upwards, and when said member has moved intoits other extreme position (Fig.

52) there left a conical passage 8 which directs the air to the bottom of the cylinder.

The member 6 is pivoted to two pairs of c'anlz arms 9, 10 of equal length keyed to parallel shal'ts ll, 12. The shaft 11 receives oscillatory i'novcment 'lrom a cam or eccentric 18 on the usual cam shait't ll so that the lllOll'lbOi' 6 assumes its uppermost position when the downwardly moving piston uncovers the scavenging ports 3, and its lowermost position when said ports are unmasked during the return stroke of the piston.

The member 6 may be ol. light sheet iron and may be conntcrlmlaneed by a weight or a spring so that its actuation does not consume an agpreciable amount of power.

What I claim is:-

l. scavenging means for double-acting two-stroke internal combustion engines, comprising, an engine cylinder. at least one scavenging air port in substantially the middle of the cylinder. a laterally movable men'iber surrounding part of the cylinder adjacent the scavenging air port, the mem her having guiding means tor scavenging air inclined to the cylinder axis toward both ends of the cylinder and positioned for comniunicating alternatively with the air port.

2. scavenging means for double-acting two-stroli'e internal combustitm engines, comprising, an engine cylinder, at least one scavenging air port in substantially the mid dle of the cylinder, an external laterally movable member embracing part of the cylinder adjacent the scavenging air port, the member having guiding means for scavenging air inclined to the cylinder axis toward both ends of the cylinder and positioned for comn'nmicating alternatively with the air port.

3. Scavenging means for double-acting two-stroke internal combustion engines, comprising, an engine cylinder, at least one scavenging air port in substantially the mid dle of the cylinder, a laterally movable member si'u'rounding part oi the cylinder adja cent the scavengil'ig air port. the member having guiding means for scavenging air in clincd to the cylinder axis toward both ends of the cylinder and positioned ferrommunicating alternativel with the air port, an air inlet chamber for the air port having walls inclined to the cylinder axis toward both ends of the cylinder, inlet ports for the scavenging air being formed alternative ly by the ctmi ieration of the inclined guid ing means of said laterally movable mom-- her. and the inclined inner surilaccs o l. the walls of the air inlet chamber.

at. Scavenging means for double-acting two-stroke internal con'ihustion engines,

comprising, an engine cylinder, atleast one scavenging air port in substantially the middle of the cylinder, an external laterally movable member surrounding part of the cylinder adjacent the scavenging air port, the menil'ier having guiding means for scavenging air inclined to the cylinder axis toward both ends of the cylinder and p0sitioned for communicating alternatively with the air port, an air inlet chamber for the air port having walls inclined to the cylinder axis toward both ends of the cylinder, inlet ports for the scavenging air being formed alternatively by the cooperation of the inclined guiding means o'li said laterally movable member, and the inclined inner surfaces ol' the walls of the air inlet chamber.

5. Scavenging means for double-acting, two-stroke internal combustion engines, comprising, an engine cylinder, at least one scavenging air port in substantially the middle of the cylinder, a laterally movable men'iber surrounding part of the cylinder ad jacent the scavenging air port, the member having guiding means for scavenging air inclined to the cylinder axis toward both ends of the cylinder and positioned for communicating alternatively with the air port, wo parallel shafts, two pairs of crank arms oii equal length carried by the shafts and connected to the laterally movable member, and means tor oscillating one of the shafts in timed relation with the reciprocation of the engine piston.

(i. Scavenging means for double-acting two-stroke internal combustion engines, com 'irising, an engine. cylinder, at least one s avenging air port in substimtially the middle of the cylinder, a laterally movable menu ber surroui'uling part of the cylinder adjacent the scavenging air port, the member having guiding means for scavenging air inclined to the cylinder axis toward both ends oi the cylinder and positioned for comma air port, an

nicating alternatively with the air inlet chamber for the air port having walls inclined to the cylinder axis toward both ends oi the cylinder, inlet ports for the scavengii'ig air being formed alternatively by the cooperation oi? the inclined guiding means ol said lateral movable member. and the inclined inner surfaces of the walls of the air inlet chamber, two pa a'llel sha'lls, two pairs of crank arms o'l equal length carried bv the shafts and connected to the laterally movable mcmbenand means for oscillating one oi the shafts in timed relation with the reciprocation of the engine piston.

In testimony whereof? I aillx my signature. 1

PIETER KUYKEN. 

